In principle each (or at least most) VCA can be used for a lot of voltage
controlles applications (filters, phasers, oscillators, VCADSR's, and many
more). As the SSM2164 has current outputs it is very easy to built a filter
(e.g. state variable or 24dB LP) around the SSM2164 by adding a capacitor
(or a capacitor in the feedback loop of an OpAmp) to each output. There are
a lot of filter applications around the SSM2164 available in the internet.
Try e.g. "SSM2164 filter" in Google and you will find a lot of examples. We
also developed a SSM2164 based filter about 2-3 years ago (during the A-107
design where we use the SSM2164 as a quad VCA) but never published this
information as we could not find anything special in this filter (and we
already have so many filters available).

Best regards
Dieter Doepfer
Doepfer Musikelektronik GmbH
Email address: hardware@...
Web Site: www.doepfer.com

> -----Ursprüngliche Nachricht-----
> Von: Doepfer_a100@yahoogroups.com
> [mailto: Doepfer_a100@yahoogroups.com ]Im Auftrag von Martin Rudling
> Gesendet: Montag, 3. April 2006 10:31
> An: Doepfer_a100@yahoogroups.com
> Betreff: RE: 1 Re: technichals...
>
>
> Thanks!
>
> It´s a bit funny, I think, that they (A&H) have chosen such an atypical

chip

> for filtering. I have been reading the info at "analog devices" and this
> application is just mentioned very briefly. Anyhow, it sounds great as a
> filter, but provides no selfoscillation. But I´m doing fine without.
> Maybe my selling of the Mutronics-LP-filter and Analogue
> Systems FB3, can
> say something about the quality. I´m actually gonna use the money to buy
> another VF-1, to get 24dB in stereo. But this choice is very much because
> I´m lazy, and I find the manner of speaking "less is more" to be
> very true
> regarding audio-machines, but that´s me...
> If the Mutator had been multimode I´d keep it, but LP only just
> makes me
> frustrated while tweaking. And of course the VF1 valves and the midi
> (without passing a MCV interface) is attractive to the restless
> personality.
> I´m sending the Kenton M-CV to a modularist in the south of Sweden today.
> The only thing I still have pure analogue is the AnaSys filterbank. I´ve
> changed my mind on that one to, I´m selling it. Same price: 2500
> SEK, that
> should be 270 EUR. I have one adjustment to offer you, though..: I´ll pay
> the shipping for you! (Europe)
>
> Best regards
> /Martin
>
>
>
>
>
> >From: "selfoscillate" < synaptic_music@... >
> >Reply-To: Doepfer_a100@yahoogroups.com
> >To: Doepfer_a100@yahoogroups.com
> >Subject: 1 Re: technichals...
> >Date: Mon, 03 Apr 2006 05:56:12 -0000
> >
> >
> >hello martin,
> >
> >over the weekend i checked my technical
> >documents about the ssm2164 again.
> >this chip can be found in several modules.
> >for example, blacet uses it a lot. usually
> >the ic itself is not configured to work as
> >a filter, but it can be found in vcf's
> >as a support chip to make parameters
> >voltage-controllable or for mixing of
> >filter stages (like in the a107).
> >
> >as others pointed out, the ssm2164 can of
> >course be used as a filter circuit, but
> >that doesn't seem to be the typical purpose.
> >the only module i found where the ssm2164
> >is also configured as a filter is the blacet
> >improbability drive, but this module cannot
> >be used for filtering of a given signal,
> >as there is no filter input jack available.
> >so i cannot say anything about it's sound
> >as a filter. all i can say is that the ssm2164
> >is doing a great job as vca, but thats obvious.
> >
> >best wishes
> >
> >ingo
> >
> >
> >
> >--- In Doepfer_a100@yahoogroups.com , "Martin Rudling"
> ><martinrudling@...> wrote:
> > >
> > > Ooops sorry I hit the send button by mistake...
> > >
> > > Well I´ll use the opportunity to thank you all for your input!!
> > >
> > > Thanks!
> > >
> > > And also I would like to encourage those who are having thoughts of
> >adding
> > > some valves to your modular. It´s ssooo nice!! Fat, creamy,
> >organic, hot and
> > > you name it...
> > >
> > > It seems like the mutator is sold today, to a friend of mine. And I
> >have
> > > found a second FB3 for sale in England, so I think I´ll buy it, to
> >go
> > > stereo, which means that my unit is no longer for sale.
> > >
> > > m
> > >
> > >
> > >
> > >
> > > >From: "Tim Stinchcombe" <timothy@...>
> > > >Reply-To: Doepfer_a100@yahoogroups.com
> > > >To: Doepfer_a100@yahoogroups.com
> > > >Subject: 1 Re: technichals...
> > > >Date: Thu, 30 Mar 2006 20:44:52 -0000
> > > >
> > > >Hi Martin,
> > > >
> > > >The SSM2164 is made by Analogue Devices:
> > > >
> > > > http://www.analog.com/UploadedFiles/Data_Sheets/15183786ssm2164.pdf
> > > >
> > > >which with the right know-how can be turned into a 4-pole 24dB
> > > >filter, or from what Allen Heath have at their website for thr VF-
> >1,
> > > >2 x 2-pole state-variable filters (so basically 12dB each), which
> > > >thus give low-, high- and band-pass, and which if run one after the
> > > >other gives 24dB (hence the 'mono' switch on the back).
> > > >
> > > >I suspect a lot of the quality of the sound comes from the
> > > >overdrive/clipping introduced by the valve input section, but
> >that's
> > > >only a guess - the total sound will depend on both chip and valves,
> > > >but how much it would change, say, if the valves were replaced by
> > > >transistors would probably be difficult to guess without trying it!
> > > >
> > > >Tim
> > > >
> > > > > I´ve asked Allen & Heath tech support what chips they used for
> >the
> > > >VF-!
> > > > > analogue valve stereo-filter. I didn´t get much wiser from the
> > > >answer
> > > > > though.
> > > > > Maybe some one here knows about the chip SSM2164
> > > > >
> > > > > (As you will see this is cuts from 2 different e-mails)
> > > > >
> > > > > >>>The active circuitry in the VF-1 is based on the SSM2163 Quad
> > > >VCA IC in
> > > > > an analogue filter configuration, supported by standard TL072
> >op-
> > > >amps
> > > > > and of course a pair of ECC82 valves.
> > > > > >Thanks for your reply. Please note the typo in my last reply
> >and
> > > >the fact
> > > > > >that it is the SSM2164, not 2163 IC that is the active VCA.>>>
> > > > >
> > > > > I´m curious, cuz I really love the sound of this machine, and I
> > > >wonder how
> > > > > much of this amusement is due the valve/overdrive section...
> > > > >
> > > > >
> > > > > >
> > > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> >
> >
> >
> >
> >
>
>
>
>
>
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